THE TILBURY FORTAt the entrance to the river Thames, opposite Gravesend

Many thanks to Alan Tilbury, U.K., for supplying
the 4 pictures of inside the Fort

Built low lying with extensive earthworks to withstand heavy bombardment
from enemy ships attempting to enter the Thames.

Sir Martin Beckman's original plan was of a pentagon;
the bastion next the water was never built, although piles were sunk.

The Water Gate of 1672.

[The Fort was]
"originally built as a kind of block-house by Henry VIII. but enlarged into a regular fortification by Charles II. in 1667."[defensive works designed by Sir Bernard de Gomme]
"The esplanade is very large, and the bastions the largest of any in the kingdom.
They are surrounded with a double moat, the innermost of which is 180 feet broad, and has a good counter scarp. The chief strength on the land side consists in its being able to lay all the adjacent level under water.
On the side next the river is a very strong curtain, having a strong gate in the middle called the Water Gate, and the ditch pallisadoed."
(From "The London General Gazetteer" of 1825)

In the last quarter of the 17th century artillery had become the main weapon of war.

There were substantial underground powder magazines.

December, 1746
"The papers reported that there were nearly 400 Scottish rebels cooped up in Tilbury Fort, and that most of them were transported to the Plantations."

1842:
"Within the fort are commodious barracks and other accommodations for the garrison, which ordinarily consists of a fort-major and a detachment of invalids."

In conjunction with batteries across the river at Gravesend the river was completely covered by heavy guns.

1792
"... on the platform are placed one hundred and six cannons, from twenty-four to forty-six pounders, besides smaller ones planted on the bastions and curtains." (Samuel Ireland)

This meant that the great powder magazine upriver at Purfleet, the Woolwich Arsenal, all the shipping at the great Port of London and London itself were well defended.